For years, security systems have employed video cameras and video processors that can perform some type of motion detection by watching for motion in a scene, generally by looking at differences between a current video frame and a previous video frame. If motion or motion exceeding a predetermined threshold is detected, an event is recognized. This event could create an alarm condition or trigger other actions, such as speeding up the capturing of images from the associated camera or storing captured images at a higher resolution or faster frame rate. Some security systems can be configured to distinguish different portions of the scene such that motion in some portions is considered more important than in other portions.
False alarms have become a significant drain on resources for police departments. More than 90% of all alarms sent to central alarm monitoring stations are false alarms. Moreover, more than 90% of all alarms sent to police departments are false alarms, and a significant portion of these false alarms were first screened by central alarm monitoring stations.
Some existing systems have video cameras mounted at both entries and exits to capture images of people entering and leaving the premises. Some of these systems or other systems may require that a camera be mounted on a door itself along with some type of sensor such as a doorknob sensor.
Current systems that have some type of visual verification do not perform any type of recognition at the premises but, rather, send video images to a remote central monitoring station for verification of alarms.
Certain existing alarm systems have motion detection techniques that involve the direct comparison of frames to detect motion and classify detected objects in the scene. In some of these systems, an alarm is only sent if the object is determined to be a human. Screening video based simply on whether detected motion is based on a certain class of objects (e.g., screening for humans) does not significantly reduce false alarms, if at all, because nearly all false alarms are caused by humans.